字符串判空

    public static void testArgsNull(Object arg,String msg){          if(isEmpty(arg)){              throw new RuntimeException(msg);
          }
    }    public static boolean isEmpty(Object o){        if(o==null){return true;}        if( "".equals(o) ||  "null".equalsIgnoreCase(o.toString()) || o.toString().trim().length()==0 ){                return true;
          }        return false;
    }